MA2501 Numerical Methods Spring 2015
|
|
- Jeremy Dean
- 5 years ago
- Views:
Transcription
1 Norwegian University of Science and Technology Department of Mathematics MA2501 Numerical Methods Spring 2015 Solutions to exercise set 3 1 Attempt to verify experimentally the calculation from class that the computation time is proportional to n 3 for large n for Gaussian elimination with scaled partial pivoting (The same is in fact true for the naive algorithm and the other pivoting strategies we considered as well). Solve a series of randomly generated linear systems for various sizes of n where n > 1000 and plot the logarithm of the computation time against the logarithm of n. What kind of function does this appear to be? Use MATLAB to t such a function to this logarithmic data, and comment on the calculation based on the result. Useful MATLAB functions: tic, toc, polyfit. We proceed accoriding to the text. We solve random systems of size n in MATLAB using Gaussian elimination with scaled partial pivoting for n = 1000, 1100,..., 2900, 3000, and measure the computational time t for each using tic and toc. Plotting ln t against ln n resulted in the following plot: ln t ln n This clearly looks like a linear function. We therefore used polyfit to t a linear function to this logarithmic data. The result was ln t = ln n to the number of digits given. By taking the exponential on both sides, this implies that t = e ln n Kn 3 February 01, 2015 Page 1 of 5
2 for some constant K > 0. Thus we have found experimentally that the computational time appears to be proportional to n 3 in accordance with the result from class. 2 Write a Matlab program for the solution of a linear system Ax = b in the case where A is tridiagonal. More precisely, the program should take the three non-zero diagonals of A and the vector b as input and use Gaussian elimination without pivoting for the solution of the system. Test your program on the matrix A R with main diagonal d = [4, 4,..., 4] and lower and upper diagonals a = c = [ 1, 1,..., 1], and the right hand sides b 1 = [1,..., 1] T and b 2 = [1, 2, 3,..., 200] T. Example code can be found on the webpage of the course. 3 Cf. Cheney and Kincaid, Exercise a) Prove that the product of two lower triangular matrices is lower triangular. b) Prove that the product of two unit lower triangular matrices is unit lower triangular. c) Prove that the inverse of an invertible lower triangular matrix is lower triangular. d) Prove that the inverse of a unit lower triangular matrix is unit lower triangular. e) Prove the previous statements for upper triangular matrices. a) Let L, M R n n be two lower triangular matrices. Assume that 1 i < j n. Since L and M are lower triangular we have l ik = 0 for k > i and l kj = 0 for k < j. Thus (LM) ij = l ik m kj = i l ik 0 + j m kj = 0. Thus (LM) ij = 0 whenever j > i, proving that LM is lower diagonal. b) Let L, M R n n be unit lower triangular. From the previous part we already know that LM is lower triangular. Now let 1 i n. Then (LM) ii = i 1 l ik m ki = l ik 0 + l ii m ii + k=j 0 m ki = l ii m ii = 1 1 = 1. Thus the diagonal entries of LM are all equal to 1, and therefore LM is unit lower triangular. February 01, 2015 Page 2 of 5
3 c) Let L R n n be an invertible lower triangular matrix with inverse M := L 1. Assume that M is not lower triangular. Then there exist indicies 1 i < j n such that m ij 0. Moreover, we can choose these indices in such a way that m kj = 0 for all k < i. Since LM is the identity matrix, we have (LM) ij = 0. Hence 0 = (LM) ij = i 1 l ik m kj = l ik 0 + l ii m ij + 0 m kj = l ii m ij. Since L is an invertible lower triangular matrix its diagonal elements are dierent from 0. Thus the equation 0 = l ii m ij already implies that m ij = 0, which is a contradiction to the denition of m ij. Hence M is lower triangular. d) Let L be unit lower triangular. Since det L = 1, it follows that L is invertible. Denote its inverse by M := L 1. We have already shown that the matrix M is lower triangular. Hence we only have to prove that M ii = 1 for every i. Because LM is the identity matrix, we have, similar as in the second part of this exercise, the equation 1 = (LM) ii = l ik m ik = l ii m ii. Since l ii = 1, this proves that also m ii = 1. e) Assume that U and V are upper triangular. Then U T and V T are lower triangular. Moreover (UV) T = V T U T. Thus, using the rst part of this exercise we obtain that (UV) T is lower triangular and therefore UV is upper triangular. The proof for unit upper triangular matrices is similar. Finally, the fact that the inverse of a (unit) upper triangular matrix is (upper) triangular follows from the fact that (U T ) 1 = (U 1 ) T ; the former is lower triangular and therefore the latter as well. 4 a) Assume that A R n n is invertible and has an LU factorization. Prove that the LU factorization is unique. b) Find matrices A R n n that either do not have an LU factorization, or whose LU factorization is not unique. a) Assume that A = L 1 U 1 and A = L 2 U 2 are two LU factorizations of the matrix A. Then L 1 U 1 = L 2 U 2. Since the matrix A is invertible, so are the matrices L j and U j. Thus we can multiply the equation above with L 1 2 from the left and with U 1 1 from the right. Thus we obtain the equation L 1 2 L 1 = U 2 U 1 1. Since L 2 and L 1 are unit lower triangular, so is L 1 2 L 1. Since U 2 and U 1 are upper triangular, so is U 2 U 1 1. Thus L 1 2 L 1 is a unit lower triangular matrix that is at February 01, 2015 Page 3 of 5
4 the same time upper triangular. The only possibility is therefore that L 1 2 L 1 is the identity matrix. This shows that we have L 2 = L 1 and, similarly, U 2 = U 1. Thus the LU factorization of A is unique. b) Consider the matrix A = [ ] Assume that A = LU is an LU factorization of A. Since l 11 = 1 and l 12 = 0, it follows that u 11 = a 11 = 0. This implies, however, that the matrix U is not invertible. As a consequence, also the product LU is not invertible. This contradicts, however, the fact that det A = 1, which would imply that A = LU is an invertible matrix. Thus, A cannot have an LU factorization. Consider now the case where n 2 and A R n n is the 0-matrix. Let L be any unit lower triangular matrix and let U = 0 R n n. Then LU = 0 = A, implying that we have constructed an LU factorization of A. Since there is more than one unit lower triangular matrix in R n n with n 2, this proves the non-uniqueness of the factorization. 5 Factor the following matrices into the LU decomposition using the LU Factorization Algorithm where l ii = 1 for all i. a) b) c) d) February 01, 2015 Page 4 of 5
5 a) L = , U = b) L = , U = c) L = , U = d) L = U = , February 01, 2015 Page 5 of 5
Linear Algebra Section 2.6 : LU Decomposition Section 2.7 : Permutations and transposes Wednesday, February 13th Math 301 Week #4
Linear Algebra Section. : LU Decomposition Section. : Permutations and transposes Wednesday, February 1th Math 01 Week # 1 The LU Decomposition We learned last time that we can factor a invertible matrix
More informationThe Solution of Linear Systems AX = B
Chapter 2 The Solution of Linear Systems AX = B 21 Upper-triangular Linear Systems We will now develop the back-substitution algorithm, which is useful for solving a linear system of equations that has
More information1 Multiply Eq. E i by λ 0: (λe i ) (E i ) 2 Multiply Eq. E j by λ and add to Eq. E i : (E i + λe j ) (E i )
Direct Methods for Linear Systems Chapter Direct Methods for Solving Linear Systems Per-Olof Persson persson@berkeleyedu Department of Mathematics University of California, Berkeley Math 18A Numerical
More informationDirect Methods for Solving Linear Systems. Simon Fraser University Surrey Campus MACM 316 Spring 2005 Instructor: Ha Le
Direct Methods for Solving Linear Systems Simon Fraser University Surrey Campus MACM 316 Spring 2005 Instructor: Ha Le 1 Overview General Linear Systems Gaussian Elimination Triangular Systems The LU Factorization
More informationANALYTICAL MATHEMATICS FOR APPLICATIONS 2018 LECTURE NOTES 3
ANALYTICAL MATHEMATICS FOR APPLICATIONS 2018 LECTURE NOTES 3 ISSUED 24 FEBRUARY 2018 1 Gaussian elimination Let A be an (m n)-matrix Consider the following row operations on A (1) Swap the positions any
More informationMath/CS 466/666: Homework Solutions for Chapter 3
Math/CS 466/666: Homework Solutions for Chapter 3 31 Can all matrices A R n n be factored A LU? Why or why not? Consider the matrix A ] 0 1 1 0 Claim that this matrix can not be factored A LU For contradiction,
More informationGaussian Elimination and Back Substitution
Jim Lambers MAT 610 Summer Session 2009-10 Lecture 4 Notes These notes correspond to Sections 31 and 32 in the text Gaussian Elimination and Back Substitution The basic idea behind methods for solving
More informationLU Factorization. LU Decomposition. LU Decomposition. LU Decomposition: Motivation A = LU
LU Factorization To further improve the efficiency of solving linear systems Factorizations of matrix A : LU and QR LU Factorization Methods: Using basic Gaussian Elimination (GE) Factorization of Tridiagonal
More informationCS412: Lecture #17. Mridul Aanjaneya. March 19, 2015
CS: Lecture #7 Mridul Aanjaneya March 9, 5 Solving linear systems of equations Consider a lower triangular matrix L: l l l L = l 3 l 3 l 33 l n l nn A procedure similar to that for upper triangular systems
More informationCHAPTER 6. Direct Methods for Solving Linear Systems
CHAPTER 6 Direct Methods for Solving Linear Systems. Introduction A direct method for approximating the solution of a system of n linear equations in n unknowns is one that gives the exact solution to
More informationMATH 3511 Lecture 1. Solving Linear Systems 1
MATH 3511 Lecture 1 Solving Linear Systems 1 Dmitriy Leykekhman Spring 2012 Goals Review of basic linear algebra Solution of simple linear systems Gaussian elimination D Leykekhman - MATH 3511 Introduction
More informationLinear Equations and Matrix
1/60 Chia-Ping Chen Professor Department of Computer Science and Engineering National Sun Yat-sen University Linear Algebra Gaussian Elimination 2/60 Alpha Go Linear algebra begins with a system of linear
More informationSOLVING LINEAR SYSTEMS
SOLVING LINEAR SYSTEMS We want to solve the linear system a, x + + a,n x n = b a n, x + + a n,n x n = b n This will be done by the method used in beginning algebra, by successively eliminating unknowns
More informationLinear Algebra and Matrix Inversion
Jim Lambers MAT 46/56 Spring Semester 29- Lecture 2 Notes These notes correspond to Section 63 in the text Linear Algebra and Matrix Inversion Vector Spaces and Linear Transformations Matrices are much
More informationDirect Methods for Solving Linear Systems. Matrix Factorization
Direct Methods for Solving Linear Systems Matrix Factorization Numerical Analysis (9th Edition) R L Burden & J D Faires Beamer Presentation Slides prepared by John Carroll Dublin City University c 2011
More informationMTH5112 Linear Algebra I MTH5212 Applied Linear Algebra (2017/2018)
MTH5112 Linear Algebra I MTH5212 Applied Linear Algebra (2017/2018) COURSEWORK 3 SOLUTIONS Exercise ( ) 1. (a) Write A = (a ij ) n n and B = (b ij ) n n. Since A and B are diagonal, we have a ij = 0 and
More information2.1 Gaussian Elimination
2. Gaussian Elimination A common problem encountered in numerical models is the one in which there are n equations and n unknowns. The following is a description of the Gaussian elimination method for
More informationElementary maths for GMT
Elementary maths for GMT Linear Algebra Part 2: Matrices, Elimination and Determinant m n matrices The system of m linear equations in n variables x 1, x 2,, x n a 11 x 1 + a 12 x 2 + + a 1n x n = b 1
More information30.3. LU Decomposition. Introduction. Prerequisites. Learning Outcomes
LU Decomposition 30.3 Introduction In this Section we consider another direct method for obtaining the solution of systems of equations in the form AX B. Prerequisites Before starting this Section you
More informationLecture 12 (Tue, Mar 5) Gaussian elimination and LU factorization (II)
Math 59 Lecture 2 (Tue Mar 5) Gaussian elimination and LU factorization (II) 2 Gaussian elimination - LU factorization For a general n n matrix A the Gaussian elimination produces an LU factorization if
More informationGAUSSIAN ELIMINATION AND LU DECOMPOSITION (SUPPLEMENT FOR MA511)
GAUSSIAN ELIMINATION AND LU DECOMPOSITION (SUPPLEMENT FOR MA511) D. ARAPURA Gaussian elimination is the go to method for all basic linear classes including this one. We go summarize the main ideas. 1.
More informationMATRICES. a m,1 a m,n A =
MATRICES Matrices are rectangular arrays of real or complex numbers With them, we define arithmetic operations that are generalizations of those for real and complex numbers The general form a matrix of
More informationAMS 209, Fall 2015 Final Project Type A Numerical Linear Algebra: Gaussian Elimination with Pivoting for Solving Linear Systems
AMS 209, Fall 205 Final Project Type A Numerical Linear Algebra: Gaussian Elimination with Pivoting for Solving Linear Systems. Overview We are interested in solving a well-defined linear system given
More informationMAT 343 Laboratory 3 The LU factorization
In this laboratory session we will learn how to MAT 343 Laboratory 3 The LU factorization 1. Find the LU factorization of a matrix using elementary matrices 2. Use the MATLAB command lu to find the LU
More informationAMS526: Numerical Analysis I (Numerical Linear Algebra)
AMS526: Numerical Analysis I (Numerical Linear Algebra) Lecture 12: Gaussian Elimination and LU Factorization Xiangmin Jiao SUNY Stony Brook Xiangmin Jiao Numerical Analysis I 1 / 10 Gaussian Elimination
More informationToday s class. Linear Algebraic Equations LU Decomposition. Numerical Methods, Fall 2011 Lecture 8. Prof. Jinbo Bi CSE, UConn
Today s class Linear Algebraic Equations LU Decomposition 1 Linear Algebraic Equations Gaussian Elimination works well for solving linear systems of the form: AX = B What if you have to solve the linear
More informationEE5120 Linear Algebra: Tutorial 1, July-Dec Solve the following sets of linear equations using Gaussian elimination (a)
EE5120 Linear Algebra: Tutorial 1, July-Dec 2017-18 1. Solve the following sets of linear equations using Gaussian elimination (a) 2x 1 2x 2 3x 3 = 2 3x 1 3x 2 2x 3 + 5x 4 = 7 x 1 x 2 2x 3 x 4 = 3 (b)
More informationSTAT 309: MATHEMATICAL COMPUTATIONS I FALL 2018 LECTURE 13
STAT 309: MATHEMATICAL COMPUTATIONS I FALL 208 LECTURE 3 need for pivoting we saw that under proper circumstances, we can write A LU where 0 0 0 u u 2 u n l 2 0 0 0 u 22 u 2n L l 3 l 32, U 0 0 0 l n l
More information4 Elementary matrices, continued
4 Elementary matrices, continued We have identified 3 types of row operations and their corresponding elementary matrices. To repeat the recipe: These matrices are constructed by performing the given row
More informationECON 331 Homework #2 - Solution. In a closed model the vector of external demand is zero, so the matrix equation writes:
ECON 33 Homework #2 - Solution. (Leontief model) (a) (i) The matrix of input-output A and the vector of level of production X are, respectively:.2.3.2 x A =.5.2.3 and X = y.3.5.5 z In a closed model the
More informationCS227-Scientific Computing. Lecture 4: A Crash Course in Linear Algebra
CS227-Scientific Computing Lecture 4: A Crash Course in Linear Algebra Linear Transformation of Variables A common phenomenon: Two sets of quantities linearly related: y = 3x + x 2 4x 3 y 2 = 2.7x 2 x
More informationCME 302: NUMERICAL LINEAR ALGEBRA FALL 2005/06 LECTURE 6
CME 302: NUMERICAL LINEAR ALGEBRA FALL 2005/06 LECTURE 6 GENE H GOLUB Issues with Floating-point Arithmetic We conclude our discussion of floating-point arithmetic by highlighting two issues that frequently
More information1111: Linear Algebra I
1111: Linear Algebra I Dr. Vladimir Dotsenko (Vlad) Lecture 7 Dr. Vladimir Dotsenko (Vlad) 1111: Linear Algebra I Lecture 7 1 / 8 Properties of the matrix product Let us show that the matrix product we
More informationReview of matrices. Let m, n IN. A rectangle of numbers written like A =
Review of matrices Let m, n IN. A rectangle of numbers written like a 11 a 12... a 1n a 21 a 22... a 2n A =...... a m1 a m2... a mn where each a ij IR is called a matrix with m rows and n columns or an
More informationI = i 0,
Special Types of Matrices Certain matrices, such as the identity matrix 0 0 0 0 0 0 I = 0 0 0, 0 0 0 have a special shape, which endows the matrix with helpful properties The identity matrix is an example
More informationChapter 4 No. 4.0 Answer True or False to the following. Give reasons for your answers.
MATH 434/534 Theoretical Assignment 3 Solution Chapter 4 No 40 Answer True or False to the following Give reasons for your answers If a backward stable algorithm is applied to a computational problem,
More informationMODULE 7. where A is an m n real (or complex) matrix. 2) Let K(t, s) be a function of two variables which is continuous on the square [0, 1] [0, 1].
Topics: Linear operators MODULE 7 We are going to discuss functions = mappings = transformations = operators from one vector space V 1 into another vector space V 2. However, we shall restrict our sights
More informationMath 240 Calculus III
The Calculus III Summer 2015, Session II Wednesday, July 8, 2015 Agenda 1. of the determinant 2. determinants 3. of determinants What is the determinant? Yesterday: Ax = b has a unique solution when A
More informationMatrix Factorization Reading: Lay 2.5
Matrix Factorization Reading: Lay 2.5 October, 20 You have seen that if we know the inverse A of a matrix A, we can easily solve the equation Ax = b. Solving a large number of equations Ax = b, Ax 2 =
More informationFundamentals of Engineering Analysis (650163)
Philadelphia University Faculty of Engineering Communications and Electronics Engineering Fundamentals of Engineering Analysis (6563) Part Dr. Omar R Daoud Matrices: Introduction DEFINITION A matrix is
More informationLU Factorization a 11 a 1 a 1n A = a 1 a a n (b) a n1 a n a nn L = l l 1 l ln1 ln 1 75 U = u 11 u 1 u 1n 0 u u n 0 u n...
.. Factorizations Reading: Trefethen and Bau (1997), Lecture 0 Solve the n n linear system by Gaussian elimination Ax = b (1) { Gaussian elimination is a direct method The solution is found after a nite
More informationIterative Methods. Splitting Methods
Iterative Methods Splitting Methods 1 Direct Methods Solving Ax = b using direct methods. Gaussian elimination (using LU decomposition) Variants of LU, including Crout and Doolittle Other decomposition
More informationNumerical Linear Algebra
Numerical Linear Algebra Direct Methods Philippe B. Laval KSU Fall 2017 Philippe B. Laval (KSU) Linear Systems: Direct Solution Methods Fall 2017 1 / 14 Introduction The solution of linear systems is one
More informationMatrices. Chapter Definitions and Notations
Chapter 3 Matrices 3. Definitions and Notations Matrices are yet another mathematical object. Learning about matrices means learning what they are, how they are represented, the types of operations which
More informationLecture # 11 The Power Method for Eigenvalues Part II. The power method find the largest (in magnitude) eigenvalue of. A R n n.
Lecture # 11 The Power Method for Eigenvalues Part II The power method find the largest (in magnitude) eigenvalue of It makes two assumptions. 1. A is diagonalizable. That is, A R n n. A = XΛX 1 for some
More informationNext topics: Solving systems of linear equations
Next topics: Solving systems of linear equations 1 Gaussian elimination (today) 2 Gaussian elimination with partial pivoting (Week 9) 3 The method of LU-decomposition (Week 10) 4 Iterative techniques:
More informationMatrix Factorization and Analysis
Chapter 7 Matrix Factorization and Analysis Matrix factorizations are an important part of the practice and analysis of signal processing. They are at the heart of many signal-processing algorithms. Their
More informationMatrix decompositions
Matrix decompositions How can we solve Ax = b? 1 Linear algebra Typical linear system of equations : x 1 x +x = x 1 +x +9x = 0 x 1 +x x = The variables x 1, x, and x only appear as linear terms (no powers
More informationRoundoff Analysis of Gaussian Elimination
Jim Lambers MAT 60 Summer Session 2009-0 Lecture 5 Notes These notes correspond to Sections 33 and 34 in the text Roundoff Analysis of Gaussian Elimination In this section, we will perform a detailed error
More information5.6. PSEUDOINVERSES 101. A H w.
5.6. PSEUDOINVERSES 0 Corollary 5.6.4. If A is a matrix such that A H A is invertible, then the least-squares solution to Av = w is v = A H A ) A H w. The matrix A H A ) A H is the left inverse of A and
More informationMath 22AL Lab #4. 1 Objectives. 2 Header. 0.1 Notes
Math 22AL Lab #4 0.1 Notes Green typewriter text represents comments you must type. Each comment is worth one point. Blue typewriter text represents commands you must type. Each command is worth one point.
More informationMath 552 Scientific Computing II Spring SOLUTIONS: Homework Set 1
Math 552 Scientific Computing II Spring 21 SOLUTIONS: Homework Set 1 ( ) a b 1 Let A be the 2 2 matrix A = By hand, use Gaussian elimination with back c d substitution to obtain A 1 by solving the two
More informationMTH 215: Introduction to Linear Algebra
MTH 215: Introduction to Linear Algebra Lecture 5 Jonathan A. Chávez Casillas 1 1 University of Rhode Island Department of Mathematics September 20, 2017 1 LU Factorization 2 3 4 Triangular Matrices Definition
More informationLinear Algebra Primer
Introduction Linear Algebra Primer Daniel S. Stutts, Ph.D. Original Edition: 2/99 Current Edition: 4//4 This primer was written to provide a brief overview of the main concepts and methods in elementary
More informationHani Mehrpouyan, California State University, Bakersfield. Signals and Systems
Hani Mehrpouyan, Department of Electrical and Computer Engineering, Lecture 26 (LU Factorization) May 30 th, 2013 The material in these lectures is partly taken from the books: Elementary Numerical Analysis,
More informationACM106a - Homework 2 Solutions
ACM06a - Homework 2 Solutions prepared by Svitlana Vyetrenko October 7, 2006. Chapter 2, problem 2.2 (solution adapted from Golub, Van Loan, pp.52-54): For the proof we will use the fact that if A C m
More informationLecture 9: Elementary Matrices
Lecture 9: Elementary Matrices Review of Row Reduced Echelon Form Consider the matrix A and the vector b defined as follows: 1 2 1 A b 3 8 5 A common technique to solve linear equations of the form Ax
More informationNumerical Linear Algebra
Chapter 3 Numerical Linear Algebra We review some techniques used to solve Ax = b where A is an n n matrix, and x and b are n 1 vectors (column vectors). We then review eigenvalues and eigenvectors and
More informationMatrix decompositions
Matrix decompositions How can we solve Ax = b? 1 Linear algebra Typical linear system of equations : x 1 x +x = x 1 +x +9x = 0 x 1 +x x = The variables x 1, x, and x only appear as linear terms (no powers
More informationMTH 464: Computational Linear Algebra
MTH 464: Computational Linear Algebra Lecture Outlines Exam 2 Material Prof. M. Beauregard Department of Mathematics & Statistics Stephen F. Austin State University February 6, 2018 Linear Algebra (MTH
More information. =. a i1 x 1 + a i2 x 2 + a in x n = b i. a 11 a 12 a 1n a 21 a 22 a 1n. i1 a i2 a in
Vectors and Matrices Continued Remember that our goal is to write a system of algebraic equations as a matrix equation. Suppose we have the n linear algebraic equations a x + a 2 x 2 + a n x n = b a 2
More informationTMA4125 Matematikk 4N Spring 2017
Norwegian University of Science and Technology Institutt for matematiske fag TMA15 Matematikk N Spring 17 Solutions to exercise set 1 1 We begin by writing the system as the augmented matrix.139.38.3 6.
More informationTopic 15 Notes Jeremy Orloff
Topic 5 Notes Jeremy Orloff 5 Transpose, Inverse, Determinant 5. Goals. Know the definition and be able to compute the inverse of any square matrix using row operations. 2. Know the properties of inverses.
More informationLinear Algebra Linear Algebra : Matrix decompositions Monday, February 11th Math 365 Week #4
Linear Algebra Linear Algebra : Matrix decompositions Monday, February 11th Math Week # 1 Saturday, February 1, 1 Linear algebra Typical linear system of equations : x 1 x +x = x 1 +x +9x = 0 x 1 +x x
More informationMidterm for Introduction to Numerical Analysis I, AMSC/CMSC 466, on 10/29/2015
Midterm for Introduction to Numerical Analysis I, AMSC/CMSC 466, on 10/29/2015 The test lasts 1 hour and 15 minutes. No documents are allowed. The use of a calculator, cell phone or other equivalent electronic
More informationSolving Dense Linear Systems I
Solving Dense Linear Systems I Solving Ax = b is an important numerical method Triangular system: [ l11 l 21 if l 11, l 22 0, ] [ ] [ ] x1 b1 = l 22 x 2 b 2 x 1 = b 1 /l 11 x 2 = (b 2 l 21 x 1 )/l 22 Chih-Jen
More informationA Review of Matrix Analysis
Matrix Notation Part Matrix Operations Matrices are simply rectangular arrays of quantities Each quantity in the array is called an element of the matrix and an element can be either a numerical value
More informationCS 246 Review of Linear Algebra 01/17/19
1 Linear algebra In this section we will discuss vectors and matrices. We denote the (i, j)th entry of a matrix A as A ij, and the ith entry of a vector as v i. 1.1 Vectors and vector operations A vector
More informationMatrices: 2.1 Operations with Matrices
Goals In this chapter and section we study matrix operations: Define matrix addition Define multiplication of matrix by a scalar, to be called scalar multiplication. Define multiplication of two matrices,
More informationCSC 336F Assignment #3 Due: 24 November 2017.
CSC 336F Assignment #3 Due: 24 November 2017. This assignment is due at the start of the class on Friday, 24 November 2017. For the questions that require you to write a MatLab program, hand-in the program
More informationSolving Linear Systems of Equations
November 6, 2013 Introduction The type of problems that we have to solve are: Solve the system: A x = B, where a 11 a 1N a 12 a 2N A =.. a 1N a NN x = x 1 x 2. x N B = b 1 b 2. b N To find A 1 (inverse
More informationLinear Algebraic Equations
Linear Algebraic Equations Linear Equations: a + a + a + a +... + a = c 11 1 12 2 13 3 14 4 1n n 1 a + a + a + a +... + a = c 21 2 2 23 3 24 4 2n n 2 a + a + a + a +... + a = c 31 1 32 2 33 3 34 4 3n n
More informationMath Lecture 26 : The Properties of Determinants
Math 2270 - Lecture 26 : The Properties of Determinants Dylan Zwick Fall 202 The lecture covers section 5. from the textbook. The determinant of a square matrix is a number that tells you quite a bit about
More informationMatrices and systems of linear equations
Matrices and systems of linear equations Samy Tindel Purdue University Differential equations and linear algebra - MA 262 Taken from Differential equations and linear algebra by Goode and Annin Samy T.
More informationReview Questions REVIEW QUESTIONS 71
REVIEW QUESTIONS 71 MATLAB, is [42]. For a comprehensive treatment of error analysis and perturbation theory for linear systems and many other problems in linear algebra, see [126, 241]. An overview of
More information18.06 Problem Set 2 Solution
18.06 Problem Set 2 Solution Total: 100 points Section 2.5. Problem 24: Use Gauss-Jordan elimination on [U I] to find the upper triangular U 1 : 1 a b 1 0 UU 1 = I 0 1 c x 1 x 2 x 3 = 0 1 0. 0 0 1 0 0
More informationSolving Linear Systems Using Gaussian Elimination. How can we solve
Solving Linear Systems Using Gaussian Elimination How can we solve? 1 Gaussian elimination Consider the general augmented system: Gaussian elimination Step 1: Eliminate first column below the main diagonal.
More informationOutline. Math Numerical Analysis. Errors. Lecture Notes Linear Algebra: Part B. Joseph M. Mahaffy,
Math 54 - Numerical Analysis Lecture Notes Linear Algebra: Part B Outline Joseph M. Mahaffy, jmahaffy@mail.sdsu.edu Department of Mathematics and Statistics Dynamical Systems Group Computational Sciences
More informationConceptual Questions for Review
Conceptual Questions for Review Chapter 1 1.1 Which vectors are linear combinations of v = (3, 1) and w = (4, 3)? 1.2 Compare the dot product of v = (3, 1) and w = (4, 3) to the product of their lengths.
More informationNumerical Linear Algebra
Numerical Linear Algebra Decompositions, numerical aspects Gerard Sleijpen and Martin van Gijzen September 27, 2017 1 Delft University of Technology Program Lecture 2 LU-decomposition Basic algorithm Cost
More informationProgram Lecture 2. Numerical Linear Algebra. Gaussian elimination (2) Gaussian elimination. Decompositions, numerical aspects
Numerical Linear Algebra Decompositions, numerical aspects Program Lecture 2 LU-decomposition Basic algorithm Cost Stability Pivoting Cholesky decomposition Sparse matrices and reorderings Gerard Sleijpen
More informationComputational Linear Algebra
Computational Linear Algebra PD Dr. rer. nat. habil. Ralf Peter Mundani Computation in Engineering / BGU Scientific Computing in Computer Science / INF Winter Term 2017/18 Part 2: Direct Methods PD Dr.
More informationOnline Exercises for Linear Algebra XM511
This document lists the online exercises for XM511. The section ( ) numbers refer to the textbook. TYPE I are True/False. Lecture 02 ( 1.1) Online Exercises for Linear Algebra XM511 1) The matrix [3 2
More informationMath 502 Fall 2005 Solutions to Homework 3
Math 502 Fall 2005 Solutions to Homework 3 (1) As shown in class, the relative distance between adjacent binary floating points numbers is 2 1 t, where t is the number of digits in the mantissa. Since
More informationLinear Algebra Solutions 1
Math Camp 1 Do the following: Linear Algebra Solutions 1 1. Let A = and B = 3 8 5 A B = 3 5 9 A + B = 9 11 14 4 AB = 69 3 16 BA = 1 4 ( 1 3. Let v = and u = 5 uv = 13 u v = 13 v u = 13 Math Camp 1 ( 7
More informationTABLE OF CONTENTS INTRODUCTION, APPROXIMATION & ERRORS 1. Chapter Introduction to numerical methods 1 Multiple-choice test 7 Problem set 9
TABLE OF CONTENTS INTRODUCTION, APPROXIMATION & ERRORS 1 Chapter 01.01 Introduction to numerical methods 1 Multiple-choice test 7 Problem set 9 Chapter 01.02 Measuring errors 11 True error 11 Relative
More informationLinear Algebra review Powers of a diagonalizable matrix Spectral decomposition
Linear Algebra review Powers of a diagonalizable matrix Spectral decomposition Prof. Tesler Math 283 Fall 2016 Also see the separate version of this with Matlab and R commands. Prof. Tesler Diagonalizing
More informationDepartment of Mathematics California State University, Los Angeles Master s Degree Comprehensive Examination in. NUMERICAL ANALYSIS Spring 2015
Department of Mathematics California State University, Los Angeles Master s Degree Comprehensive Examination in NUMERICAL ANALYSIS Spring 2015 Instructions: Do exactly two problems from Part A AND two
More informationMath 471 (Numerical methods) Chapter 3 (second half). System of equations
Math 47 (Numerical methods) Chapter 3 (second half). System of equations Overlap 3.5 3.8 of Bradie 3.5 LU factorization w/o pivoting. Motivation: ( ) A I Gaussian Elimination (U L ) where U is upper triangular
More informationDepartment of Aerospace Engineering AE602 Mathematics for Aerospace Engineers Assignment No. 4
Department of Aerospace Engineering AE6 Mathematics for Aerospace Engineers Assignment No.. Decide whether or not the following vectors are linearly independent, by solving c v + c v + c 3 v 3 + c v :
More informationLinear Algebra. Solving Linear Systems. Copyright 2005, W.R. Winfrey
Copyright 2005, W.R. Winfrey Topics Preliminaries Echelon Form of a Matrix Elementary Matrices; Finding A -1 Equivalent Matrices LU-Factorization Topics Preliminaries Echelon Form of a Matrix Elementary
More informationJACOBI S ITERATION METHOD
ITERATION METHODS These are methods which compute a sequence of progressively accurate iterates to approximate the solution of Ax = b. We need such methods for solving many large linear systems. Sometimes
More informationMATRIX ALGEBRA AND SYSTEMS OF EQUATIONS. + + x 1 x 2. x n 8 (4) 3 4 2
MATRIX ALGEBRA AND SYSTEMS OF EQUATIONS SYSTEMS OF EQUATIONS AND MATRICES Representation of a linear system The general system of m equations in n unknowns can be written a x + a 2 x 2 + + a n x n b a
More informationSince the determinant of a diagonal matrix is the product of its diagonal elements it is trivial to see that det(a) = α 2. = max. A 1 x.
APPM 4720/5720 Problem Set 2 Solutions This assignment is due at the start of class on Wednesday, February 9th. Minimal credit will be given for incomplete solutions or solutions that do not provide details
More informationCSE 160 Lecture 13. Numerical Linear Algebra
CSE 16 Lecture 13 Numerical Linear Algebra Announcements Section will be held on Friday as announced on Moodle Midterm Return 213 Scott B Baden / CSE 16 / Fall 213 2 Today s lecture Gaussian Elimination
More informationCSL361 Problem set 4: Basic linear algebra
CSL361 Problem set 4: Basic linear algebra February 21, 2017 [Note:] If the numerical matrix computations turn out to be tedious, you may use the function rref in Matlab. 1 Row-reduced echelon matrices
More informationApril 26, Applied mathematics PhD candidate, physics MA UC Berkeley. Lecture 4/26/2013. Jed Duersch. Spd matrices. Cholesky decomposition
Applied mathematics PhD candidate, physics MA UC Berkeley April 26, 2013 UCB 1/19 Symmetric positive-definite I Definition A symmetric matrix A R n n is positive definite iff x T Ax > 0 holds x 0 R n.
More information22m:033 Notes: 3.1 Introduction to Determinants
22m:033 Notes: 3. Introduction to Determinants Dennis Roseman University of Iowa Iowa City, IA http://www.math.uiowa.edu/ roseman October 27, 2009 When does a 2 2 matrix have an inverse? ( ) a a If A =
More informationLecture 3: QR-Factorization
Lecture 3: QR-Factorization This lecture introduces the Gram Schmidt orthonormalization process and the associated QR-factorization of matrices It also outlines some applications of this factorization
More informationMODEL ANSWERS TO THE FIRST QUIZ. 1. (18pts) (i) Give the definition of a m n matrix. A m n matrix with entries in a field F is a function
MODEL ANSWERS TO THE FIRST QUIZ 1. (18pts) (i) Give the definition of a m n matrix. A m n matrix with entries in a field F is a function A: I J F, where I is the set of integers between 1 and m and J is
More information